Prelab Images - Inguinal Region
Prelab should consist of reading the lab manual and dissector answers and viewing the dissection video. To begin your study, you may find it useful to look over the Netter's or LWW Atlas images listed below.Osteology/Identify
Plates N248 or TG5-03 and N486 or TG3-04 and TG3-05 show the iliac crest, anterior superior iliac spine, pubic tubercle, and pectin pubis (pectineal line). The pubic crest is not labeled in these drawings, but is between the pubic tubercle and pectineal line in plate N486 or TG3-06 and TG6-04. The iliopectineal line is labeled in plate TG6-04.Step 1. Examine the round ligament of uterus or spermatic cord and inguinal canal. (Play movie)
Plate N387 or TG6-31 shows the spermatic cord and plate N400 or TG5-09 shows the round ligament of the uterus. Plate N263 or TG5-08 and TG5-09 identify the lacunar and pectineal ligaments, which you will see better later. See Objective 8 and plates N387 or TG6-31 and N390 (bottom) for the discussion of the descent of the gonads (and which layers of abdominal wall form which layers of spermatic cord covering). Plates N497 or TG3-14 and N498 show the genitofemoral nerve at its origin and plates N387 or TG5-08 shows this nerve innervating the cremaster muscle. Plate N251 or TG5-10 shows the continuity of the cremaster muscle with the internal abdominal oblique. Try to dissect and remove the cremaster muscle from the round ligament of the uterus if identifiable. Plate N259 or TG5-10 gives a good look at the falx inguinalis and the weak fascia (labeled transversalis fascia within the inguinal triangle, site of direct hernia). Plate N259 or TG5-10 also shows the inferior epigastric artery and vein and the lacunar ligament. Plate N260 labels the transversalis fascia, which also forms the internal spermatic fascia (N387 or TG5-10 and N390) in the male. Plate N259 or TG5-08 labels the deep inguinal ring (formed by transversalis fascia) as it transmits the elements that make the spermatic cord (the deep ring is where the spermatic cord is formed) or round ligament of uterus in female (TG5-09). Plate N260 or TG5-10 shows the inguinal canal. Plate N387 or TG6-31 (N262 or TG5-10B and TG5-10C may also help) shows the ductus deferens, testicular artery, pampiniform plexus, and genital branch of genitofemoral nerve.Step 2. Incise the complete thickness of the abdominal wall transversely at the umbilicus. (Play movie) & Step 3. Examine the anterior abdominal wall below the incision, defining the folds and fossae in the peritoneum. (Play movie)
Cut through the entire abdominal wall (including the parietal peritoneum in plate N260 or TG5-10B) below the level of the umbilicus. Cut through the anterior abdominal wall on the left side vertically - from the level below the umbilicus inferiorly towards the inguinal canal. Now you may be able to see the inguinal canal better (N260 or TG5-10A). Plate N260 or TG5-10B shows the parietal peritoneum, extraperitoneal connective tissue, and transversalis fascia layers. Plate N253 or TG5-07 shows the median umbilical fold, (created by median umbilical ligament/urachus) the medial umbilical fold (created by medial umbilical ligament which is the obliterated umbilical artery), and the lateral umbilical fold (created by inferior epigastric vessels). This plate also labels the supravesicular fossa. The medial inguinal fossa (between medial and lateral umbilical folds) and lateral inguinal fossa (lateral to the lateral folds) are shown, but not labeled in plate N253 or TG5-07. Plates N253 or TG5-07 and N259 or TG5-10 show the relations of the fossae to the weak fascia and deep inguinal ring.Step 4. Examine the internal aspect of the inguinal region, defining the deep inguinal ring, inguinal triangle, and associated structures. (Play movie)
Plate N253 or TG5-07 shows the parietal peritoneum being removed to expose the median umbilical ligament, medial umbilical ligament, and inferior epigastric vessels. Plates N253 or TG5-08 and N259 or TG5-30 show the inguinal triangle. Plates N253 or TG5-33 and N263 or TG5-33 label the psoas muscle. Remove the peritoneum and extraperitoneal fat from the pubic pectin and the psoas muscle. Plate N253 or TG5-08 and TG5-09 shows the lacunar and pectineal ligaments from inside the abdominal cavity. Plate N255 shows the inferior epigastric vessels piercing the transversalis fascia. Plate N253 or TG5-07 shows the deep inguinal ring lateral to the inferior epigastric vessels with the ductus deferens and testicular vessels passing through it. Plates N253 or TG5-07, N259 or TG5-10, and N260 review the falx inguinalis, weak fascia, deep and superficial inguinal rings, inguinal canal, and inguinal ligament. A direct hernia will pass through the inguinal triangle (N253 or TG5-11C) and pass through the weak fascia of plate N259 or TG5-10. An indirect hernia will pass through the deep inguinal ring (N253 or TG5-07) and follow the spermatic cord (N261 or TG5-11B). Plate N260 shows the inguinal canal. Plates N387 or TG6-31, N390, and objective 3 review the coverings of the spermatic cord and the descent of the gonads. Plate N389 shows the round ligament of the uterus and its male homologue the scrotal ligament (mislabeled 'gubernaculum' in plate N389).
Updated: 21 November 2011
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